MADRID, August 12, 2008 (AFP) - Spain's transport ministry said Tuesday it was investigating Irish budget airline Ryanair over its decision to cancel thousands of reservations made on third-party websites.

It said the probe was aimed at 'obtaining information' about Ryanair's announcement that it will not honour tickets bought on 'unlawful' price-comparison websites such as lastminute and eDreams.

The no-frills carrier has said that from August 11 only bookings made on its own website and its telephone reservations line would be valid.

The Spanish-based eDreams announced that it would take action against Ryanair for 'irresponiblity and negligence' and the harm it has caused by the 'unilateral cancellation of thousands of paid and confirmed reservations.'

A Spanish consumer group, Facua, also condemned the decision by Ryanair, which it said had 'failed to fulfil its contractual obligations between passenger and transporter.'

Ryanair promised that passengers affected would be refunded, but Facua said the carrier should also pay them compensation for the inconvenience caused.

Ryanair says it took the action against the so-called screen scraping websites in part because they are levying 'unnecessary' handling charges, they do not provide up to date flight information and they are delaying access to the airline's own website by its customers.

The airline has already taken legal action against two sites, Ireland's Bravofly and V-tours of Germany, to prevent them from listing Ryanair flights.

The carrier announced last month that its net profit had dived 85 percent during its first quarter as the cost of fuel rocketed.